V4L (926_2): Moves compat32 functions from fs to v4l subsystem

This moves the 32 bit ioctl compatibility handlers for
Video4Linux into a new file and adds explicit calls to them
to each v4l device driver.

Unfortunately, there does not seem to be any code handling
the v4l2 ioctls, so quite often the code goes through two
separate conversions, first from 32 bit v4l to 64 bit v4l,
and from there to 64 bit v4l2. My patch does not change
that, so there is still much room for improvement.

Also, some drivers have additional ioctl numbers, for
which the conversion should be handled internally to
that driver.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@brturbo.com.br>